Absorbent articles, such as diapers, incontinence garments and the like, are generally capable of absorbing multiple discharges of liquid from the wearer. As a result, the use condition of the absorbent article is not readily apparent from casual inspection. It has often been necessary to reach into the garment or open the garment to touch and feel the degree of dampness therein. This task may be unpleasant. In addition, the article may contain superabsorbent materials, which efficiently hold liquids, but may obscure the feeling of dampness within the absorbent article. Because of the difficulty in gauging the dampness condition of the article, the article may be left on the wearer for too long a time period. The absorbent capacity of the article may be exceeded and the skin of the wearer may become overly hydrated. As a result, the diaper may leak and become discomforting to the wearer.
Certain attempts have been made to provide a device for indicating the degree of wetness within a diaper. For example, U.S. Pat. No. 2,681,032 issued June 15, 1954 to J. Shaw describes a diaper which includes a device for indicating a condition of dampness therein. The device comprises a stretched resilient member, such as a rubber band, connected with a frangible means which has so low a wet strength that it is broken by the contractile force stored up on the resilient member. The breaking of the frangible means allows the resilient member to contract and move an indicator into a portion where it can be viewed.
U.S. Pat. No. 4,022,211 issued May 10, 1977 to T. Timmons, et al. describes a wetness indicator which employs a water-dispersible dye printed in a selected pattern onto an absorbent article. A disappearance of the dye pattern indicates the presence of water within the article. Other types of dye indicators employ liquid-activated dyes which become visible when wetted.
Another type of detection device is described in U.S. Pat. No. 4,484,573 issued Nov. 27, 1984 to K. Yoo. This device employs an electronic alarm mechanism to detect moisture within a diaper.
Liquid-contractible elastic materials have been known in the art and have been employed to elasticize particular portions of a disposable diaper. For example, U.S. Pat. No. 4,357,938 issued Nov. 9, 1982 to O. Ito, et al. describes a disposable diaper comprising a water-absorbing layer located between a liquid-permeable surface sheet and a liquid-impermeable backing sheet. A means is provided so that the water-absorbing shrinkable fibers become wetted when the diaper is wetted and thereby shrink to elasticize the diaper edge. Similarly, U.S. Pat. No. 4,623,342 issued Nov. 18, 1986 to Ito, et al. describes a disposable diaper having water-absorptive, shrinkable fiber strings to form gaskets against the legs and thighs of the wearer.
Conventional dampness indicators, however, have not been sufficiently able to gauge the dampness condition within an absorbent garment, and have not provided an adequate signal of the appropriate time to change the garment. As a result, the garment may be left on the wearer for too long a period thereby allowing leakage of fluids from the diaper and causing discomfort to the wearer.